Housing for oil burners



Feb. 1, 1949. E. c. STAUFFER HOUSING FOR O IL BURNERS- Filed Oct. 24, 1946 2 Sheets-Sheet 1 FIG],

INVENTOR. EARL c. STAUFFER E. C. STAUFFER HOUSING FOR OIL BURNERS Feb. 1, 194 9.

7 Filed Odt. 24, 1946 2 Sheets-Sheet 2 INVENTOR. EARL c. STAUFFER Patented Feb. 1, 949' s UNITED. sures AT ENT I i Q 2,460,370 V noos no FOR on. J nan-Ens Earl C. Staufler, Lancaster, Pa, Application Qctober 24 19 26, Serial No. 765,468 4 Claims. (01. 230- -133) My invention relates to a housing for oil burners and more particularly, to] a housing for soe led'su r e burne e inv n on s 1 cern'edparticularlywith a housing which is so constructed and arranged that the air delivery therefrom is substantially uniform, thus, obviating objectionable combustion noisesand insuring betterand'more uniform burning of the fuel.

The, principal object of my invention, therefOX'efiSj'tO provide a gun-type burner housing which will provide for eoonom'ical and efficient fuel burning, and at the saine time provide a supply of air for combustion which will be delivered at a substantially constant velocity to obviate the pulsating combustion noises which commoniy occur in this type of burner and which are not only objectionable from the noise standpoint, but'also result in'poor firing and excessive fuel consumption.

'In order that'my invention may be readily understood, I shall describe the same in conjunction with the attached drawings in which:

Figure l is a perspective view illustrating one embodiment of my invention; and

Figure 2 is a sectional View taken along the line II-- II of Figure 1.

The housing of the present invention includes a novel combination of draft tube and scroll with an air reservoir anda limiting orifice positioned between the draft tube and the air reservoir. It will be understood from the description which follows, that while each of these novel elements is included in combination with the others in the preferred embodiment of my invention which is V illustrated in the drawings, certain of these novel elements may be incorporated in a blower housing'alone or in combination withother of the elements and not necessarily. all of them. a For optimum efliciency and noiseless operation, I prefer, of course, to incorporate all of the novel elements in' the combination referred to.

Referring now to. the drawings, the draft tube 2 ispreferably formed of sheet metal, although the same may be cast from iron or other materials, if desired. The tube 2 has an exhaust opening 3 at its forward end which is adapted to be positionedwithin or adjacent the fire box of a boiler or the like. Where the draft tube 2 is formed of mild steel, it is desirable to provide a stainless steel tip 14 which is positioned about the opening 3 in the draft tube and extends forwardly therefrom. If the draft tube is formed of cast iron or of stainless steel, then, of course, a stain ss s l t p cir tip of other heat res in material is not necessary.

in the embodiment illustrated, the draft tube is tapered from theeahaust-end Q to. the'in'let e11d; ear s. he nl en 5 s eds q a e i isection. In a ty al en boaiment, theopening smarts 3 e iat a1 i1. I may be if square, length of the tube from the end of the tube ro er to, theiimitingnnfice a may b whil I pret o. runthe draft tube a circular cross section at'the exhaust to a s ua e or eotansularconfiguration at the inlet end, I may-maize both ends-circular in e9 e t enj o other c nfisuration if desired,

o fiqllfii i'e or rectangular conzh he cwsssectional area e ziub e i cte -e i et end-andof u se. nc eas s he a apaci a-of the tu e without increasing its-length and without in: creasing the width of the'honsing beyond the minimum shown, which 'isabqut 4%".

There is a decided advantage having the ra tu aper om. a a lers c 're tane a r s ect at he nlet n toe ei cul r'cross section at the exhaust end, tor by such construe:

i leakin the nls nation, I inc ion, ov de nlar ed a ea irect w -d of the limiting orificet which eiiecti-ve'for eheaeieg es ew-of i n o an ro g t e ub as =wi xbe m re'i s e after described. The square surt acesdisposed ie ly ie wei i 1 e o n n in the inn ting orifice. also serve toprevent any tendency for e al surrli d by the from ioll'owinsa e cal. path down the tube to the exhaust end 3.

The scroll iis preferably formed of light gauge,

. mild steel and is; welded to themain body-aiof the housing and also to the end plates-9- and I561. The scroli l is provided with a cutoii' .H which is formed integrally with the scroll and, inthe embodiment illustrated, is formed folding the.

, metai back into a bend {2. By this means, it

possible to avoid the creation or whistling noises which commonly-seem when the-cutofi issnarp. The scroll disposed in the conventional mane ner to. provide ior an increased area in the direction travel of the blower wheel Hwhich is diagrammatically shown in Figure ibut has been omitted in Figure .2 ior clasity of illustration of other parts. The wheel is mounted upon a shaft id for rotation in the direction of the, arrow in Fi ure 1- In he' mb d ment il t e the blower wheel is 5i/ ijnoutside diameter and has an efiective width 31%". This asirocco type lower h e a d i wan d to ro a e at be ween 1725 and 1750 R. P. M. l

Th Q i iOQ 9 h smel respec o h draft tube is important in the present invention and constitutes a radical departure from the prior art. In prior art blowers, it has been common practice to rotate the blower wheel so that the air delivered by the fan is injected directly into the draft tube. This has been also controlled by the position of the cutoff. According to the present invention, the direction of the rotation of the fan is reversed from that normally employed and the cutoff is so positioned as to provide for the delivery f air to the air reservoir I5, as will be more fully hereinafter described.

A supply of air to the blower wheel may be controlled in the conventional manner by means of an air inlet I6, having ports ll through which the air in inletted. A controlling band is provided for adjusting the openings 51 so that the same may be either fully opened or closed, or

partially open, depending uponthe quantity of air to be delivered. The end plate 9 is provided with a circular opening I8 which delivers the air from the inlet and opens I? to the blower wheel. This portion of the arrangement is conventional in gun-type burners.

The opening it in Figure 1 receives the housing of a motor which drives the fan wheel I3. The motor has been removed in Figure 1 in order to better illustrate the housing. It completely fills the opening 9 so that all air inlet into the blower is through the ports I! as shown in Figure 2.

The air reservoir I5 is formed by the walls 9 and iii of the housing and the body portion 8, and is enclosed by atop plate 20. The reservoir 55 is positioned above and to the rear of the scroll i, as best illustrated in Figure 2. The cutoff Ii which defines the opening in the forward end of the reservoir I5, is positioned so that a line drawn horizontally through the center of the draft tube will be approximately tangent to the top of the scroll l. The positioning of the cutoff with respect to the draft tube is not critical in the sense that a few parts an inch will materially afiect the operation of the device, but its position should be such that air contained in the reservoir I5may be fed into the draft tube 2 through the controlling orifice 6. In the embodiment illustrated, the distance from the cutoff I I to the top plate 20 of the housing is about 2 /3 and as heretofore mentioned, the housing is about 4 wide 'so that the entrance end ofthe reservoir I 5 is defined by a rectangular opening about 2%," x 4%". The-reservoir I5 increasesin cross sectional area as the scroll I curves to meet the body 3 of the housing, and the lowermost portion of the reservoir I5 in the embodiment illustrated is formed by the intersection. of the scroll l and the body 8. This is not a critical'configuration, since the reservoir I5 may bemade wholly rectangular in cross section throughout, if desired, but for convenient fabrication and assembly with a minimum of metal and ininimuinwelding, I prefer to have tlie'reservoir I5 defined in one wall by the scroll I, since this makes for economical fabrication.

In the embodiment illustrated, the whole of the reservoir l 5 is unobstructedbut if it is necessary to carry any Wires down into the chamber from controls mounted in the plate 20, a baiile may be provided across the opening between the walls 8 and IE} and welded to the scroll i and the walls 9 and I0, thus preventing any possibility of any wires getting caught in the fan. The baiii'e would, of course, beperforated to permit the free passage of air into and out of the chamber i5.

In the. embodiment which I have chosen for illustrative purposes, thecapacity of the reservoir I5 is about 87.6 cubic inches. This may be varied, of course depending on the size of the oil burner for which the housing is adapted, the cubical displacement of the fan per minute and other variable factors.

The top plate 2t] may be hinged to the body 3 so as to permit ready access to the interior of the blower housing; In the housing illustrated, the top plate 20 .is provided with an upright or vertical mounting plate. 2| which is adapted to receive a combustion control. The plate 20 is also provided with appropriate openings for the reception and wiring of other components of the oil burner. It will be obvious that the components may be placed on the blower housing as illustrated or may be remote therefrom as desired. The mounting of the components for the control of the burner mechanism on the housing constitutes no part of the present invention. The top plate may be plain, if desired.

The opening between the reservoir I5 and the draft tube 2 is defined by the limiting orifice "i, referred to above. The orifice 6 is preferably of circular cross section and in the embodiment described above where the draft tube has an exhaust orifice 3" in diameter and an inlet 4" square, the limiting orifice 6 may be 3%" in diameter. The size of the opening in the limiting orifice 6 will depend upon the quantity of oil to be burned per hour and will be related to tional area of the exhaust end of the draft tube.

In the operation of my device, air which is introduced into the housing through the ports I! and the opening I8, is carriedby the fan I3 into the opening defined by the scroll I. The air is cut off by the cutoff plate I! and is fed into the reservoir I5. On completion of the filling of the reservoir I5 which occurs substantially instantaneously upon operation of the blower wheel, air is fed through the limiting orifice 6. Since the limiting orifice 6 is of lesser cross sectional area than the cross sectional area of the draft tube immediately adjacent thereto, the air expands into the draft tube and moves therealong, being compressed slightly as it moves from the inlet to the exhaust end of the draft tube. This is due, of course, to the tapering of the draft tube. While I donot wish to be limited to the following theory, it is oifered as an explanation of the improved results which are achieved by the provision of the limiting orifice 6 at the inlet end of the draft tube. In operation of the blower wheel, air is delivered into the zone behind the limiting orifice 5 in a nonuniform manner and by restricting the cross sectional area of the inlet orifice to a value less than the cross sectional area of the draft tube, the total volume of air which is delivered through the limiting orifice is substantially uniformly distributed therethrough, for there is a tendency to build up a slight back pressure at the inlet orifice which is greater than the pressure which would be built up if the limitin velocity at the inlet end and is compressed uniformly throughout the length of g the draft in cubic feet per minute at the exhaust end of l the tube, thus insuring the best possible combustion of the fuel and guaranteeing the least combustion noise in operation.

The reservoir I also has a very important effect upon the uniform supply of air to the burner mechanism. From the previous description, it will be clear that the reservoir I5 is of substan ial capacity and in actual test, I have determined that a pressure can be built up in the reservoir equal'to about 1 of water. This varies depending upon conditions of operation and other variable factors, but in any event there is a substantial head pressure built up in the reservoir and this is effective for supplying air to the draft tube and delivering the same at the exhaust end thereof at a substantially uniform velocity. If there is any tendency for the blower wheel to slip, air is bled from the reservoir directly into the draft tube, thus avoiding the setting up of any variable pressure due to the drop-in volume in the draft tube; this is common with conventional burners of the gun-type and results in excessive'combustion noise.

By providin a reservoir for the air to be delivered to the draft tube, it is also possible to elimi nite rarefaction and compression of air due to irregular draft pull and other causes.

In a small oil burner adapted to burn about 1 /4 to 1 /2 gallons per hour, I have successfully delivered air at a substantially uniform velocity through the exhaust end of the draft tube; Whereas, with similar, but conventional equipment, the velocity of air will in practically all instances vary about the periphery of the exhaust end of the draft tube, being generally measured as an average delivery through the tube. It is this non-uniformdelivery, at the periphery where combustion occurs, which results in inefficient burning and also considerable noise due to the uneven and periodic blasting of portions of the flame. Thus my invention offers a real contribution tothe art of efficient burning of fuel, coupled 6 I claim: 1. In an air supply system for a gun type fluid fuel burner, a tapered draft tube having a circular exhaust opening and a substantially rectilinear inlet opening, and a constricting plate disposed in theinlet opening, said plate having an opening therein, the cross sectional area of which is greater than the cross sectional area of the exhaust opening and less than the cross sectional area of the inlet opening. v

2. In an air supply system for a gun type fluid fuel burner, a tapered draft tube having a substantially circular exhaust end and a substantially rectilinear inlet end, said tube tapering from said inlet end to said exhaust end, and a substantially rectilinear plate disposed in the inlet end of said tube and having a substantially circular opening therein to provide areas for the expansion of air directed through said circular opening in the plate forwardly thereof alon the direction of travel of air through said tube.

3. In an air supply system for a gun type fluid fuel burner, a draft tube having an inlet opening and an exhaust opening, said exhaust opening being substantially smallerthan the inlet opening, said tube being gradually constricted from said inlet opening to said exhaust opening, and constricting means limiting the opening. at said inlet end to a cross sectional area greater than the exhaust end and substantially less than the cross sectional area of the draft tube immediately forward thereof in the direction of travel of air through said tube.

4. In an air supply system for a gun type fluid fuel burner, the combination of a housing, a, scroll formed therein, a draft'tube extending from the housing, a reservoir formed in the housing having a portion thereof defined by said scroll, and cutoff means for said scroll serving to direct the air supplied to said scroll, said cutoff means being disposed so that a line drawn tangential thereto and substantially horizontally of the housing will intersect the draft tube about midway of the opening therein. I

- EARL C. STAUFFER.

REFERENCES CITED "The following references are of record in the file of this patent;

UNITED STATES PATENTS Number Name Date 1,601,242 Ennis Sept. 28, 1926 1,663,993 Schmidt Mar. 27, 1928 1,679,326 Mitro July 31, 1928 2,035,012 Relf Mar. 24, 1936 2,242,616 OBrien May 20, 1941 

